Well, if it was the shifter bushing, it would just be a wobbly stick, gas or no gas, in gear, in neutral, always wobbly. You could feel that play, as in move the stick any direction and it goes a bit before you feel it moving the gear selector, so you'd likely know by feel if that was the issue.
You can check the bolts of the tranny case and make sure it's mated properly to the engine block. Loose bolts would be bad and allow the tranny to move on it's own, moving your stick around. This could be the result of shade tree mechanics doing a clutch job or something and not torquing the bolts properly.
You can check your motor/ tranny mounts and see if the are so deteriorated that the rocking of the engine during acceleration or braking is what's moving your stick around. Your car is getting up there in years. You might be able to see that type of movement if you pop the hood and gas the engine to see how much twist you're getting and maybe you'll see the shifter linkage moving at the firewall or wherever it goes to your interior. This is my suspicion and I'd start here if it's not the loose play I first describe.
Worst case, the internals are coming loose or wearing out and creating play. I doubt this, but it's not impossible. Here is a link to the Tranny chapter of the FSM for your '95 Altima:
http://www.nicoclub.com/service-manual? ... ma/1995/mt